I would have thought it was fine, as long as you aren't using it right up against the cervix. I use mine lower down, directed at the front.
The things they are avoiding are gels and antibiotic creams and probably the 0.01% oestrogen creams where you have to put a fair wodge of it in the vagina the night before, and it all falls out in the morning. Or ky gel and lubricants. I don't know about moisturisers like replen; probably best left a day.
I would miss the one the night before, because it will not have gone completely and the gel it forms will probably come out on the speculum. Then use one straight after.